The present invention relates to an airdistribution cap which is to be fitted on top of a heating or air-conditioning unit with natural or forced convection and the function of which is to regulate both the flow-rate and the direction of the air output by the convector.
Heating units normally used for domestic or office heating comprise a finned heat-exchanger with a pipecoil for the circulation of hot water-connected to the heating system of the habitable unit—and a housing with openings at the bottom and at the top for promoting the circulation of air into the unit and through the finned exchanger.
There are two types of such heating units: units with natural convection and units with forced convection (fan convectors). In fan convectors, a fan is disposed beneath the finned exchanger and creates forced air convection extremely efficiently. In natural-convection units, on the other hand, the air-flow is caused by movements present in the fluid mass owing to disequilibria of forces caused by the heat-transmission process. When the exchanger is supplied with hot water, convection is initiated owing to the pressure difference existing between the column of still, cold air outside the convector and the column of hot air present inside the convector, so that a true chimney effect is created.
It is also known to cover conventional thermosiphonic heaters or radiators with suitable housings both to improve their appearance and to prevent dispersal of heat in directions which are not useful from the point of view of the habitability of the room.
For this purpose, the housings or cabinets have front grills which enable the hot air-flow to be directed towards the centre of the room, thus minimizing dispersal and making best use of the heat supplied by the thermosiphonic heater or radiator. A disadvantage of this solution, which is particularly clear when the heating unit is placed beneath a window, is that the hot air-flow, which is directed forwards, cannot substantially strike the surface of the window. When the window is misted over-which normally occurs when the humidity inside the dwelling is very high and/or the outside temperature is low—a heating unit such as that described above cannot therefore demist the glass.
A first problem underlying the present invention is therefore that of providing a distribution device which can be fitted on thermosiphonic heaters, radiators, or heating or air-conditioning units with natural convection or with forced convection and which does not have the disadvantages discussed above.
A further problem towards which the present invention is directed is that relating to the need to regulate the heating power delivered by the heating unit at will, in dependence on specific environmental requirements. This operation which, in the case of fan convectors, is performed simply by switching the fan on or off, can be achieved with thermosiphonic heaters, with radiators, or with natural-convection units, only by intermittent operation of the thermosiphonic circulation of hot water.
A third problem addressed by the present invention is that of providing a device characterized by considerable constructional simplicity and versatility of use.